After Sean supposedly hooked up with Peta Murgatroyd (or at least always looks like he wants to), Catherine reportedly got fed up. According Celeb Dirty Laundry, she decided to get back at him by getting with Julz.

Apparently at a party she was seen "snuggled up" with him. "She was rubbing Julz's arm, whispering in his ear and giggling," a source told Star magazine.

That's not exactly being caught in the sack, but her behavior was apparently enough to raise some suspicions. We don't want to believe either of them could be cheating, but we've been shocked too many times before to think it couldn't happen.

There does seem to be a better explanation for her behavior with Julz though -- they've just become good friends. And it's good news for the wedding. A source told Hollywood Life:

Julz is a pro on the show and is a good friend of everyone. Julz has been teaching Catherine to dance a little bit so she and Sean can share in the experience. Julz hangs out with everyone all the time, at dinners and events etc. They are nothing more than friends and that report is honestly hysterical.

Teaching her to dance -- how perfect!

Both reports are based on "sources," so who knows where the truth lies. I'm choosing to think positive, however, and can't wait to see them waltz at their wedding.